U.S. patent application number 09/992708 was filed with the patent office on 2003-05-22 for internal medical device communication bus.
Invention is credited to Caby, Glen D., Chang, Jyhlin, Jordan, Curtis R., Neumiller, James S., Olson, Dana J., Schweizer, Scott O., Silver, Ward A..
Application Number | 20030097160 09/992708 |
Document ID | / |
Family ID | 25538647 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030097160 |
Kind Code |
A1 |
Caby, Glen D. ; et
al. |
May 22, 2003 |
Internal medical device communication bus
Abstract
In general, the invention facilitates improved inter-module
communication within a medical device system, such as an automated
external defibrillator (AED), by using a serial data interface
based on the USB specification to transfer data between modules. As
a result, data transmission rates may be improved significantly,
thereby providing ample communication bandwidth for a variety of
medical device applications. Further, the serial interconnect
nature of the USB interface reduces the number of physical
interconnects that are needed to support the interface, thereby
reducing the design constraints on the medical device system.
Inventors: |
Caby, Glen D.; (Lake Forest
Park, WA) ; Neumiller, James S.; (Redmond, WA)
; Chang, Jyhlin; (Shoreline, WA) ; Jordan, Curtis
R.; (Kent, WA) ; Olson, Dana J.; (Kirkland,
WA) ; Silver, Ward A.; (Vashon, WA) ;
Schweizer, Scott O.; (Snohomish, WA) |
Correspondence
Address: |
SHUMAKER & SIEFFERT, P. A.
8425 SEASONS PARKWAY
SUITE 105
ST. PAUL
MN
55125
US
|
Family ID: |
25538647 |
Appl. No.: |
09/992708 |
Filed: |
November 19, 2001 |
Current U.S.
Class: |
607/60 |
Current CPC
Class: |
A61N 1/025 20130101;
A61N 1/3956 20130101; A61N 1/08 20130101; A61N 1/3904 20170801 |
Class at
Publication: |
607/60 |
International
Class: |
A61N 001/08 |
Claims
1. A method comprising: transmitting a USB token packet to a first
module of a medical device; when the first module has a data packet
to transfer, receiving the data packet from the first module; and
transferring the data packet to a second module of the medical
device using a USB protocol.
2. The method of claim 1, further comprising encoding the data
packet using an NRZI encoding scheme.
3. The method of claim 1, further comprising transferring the data
packet in one of an isochronous mode, an interrupt mode, a bulk
data transfer mode, and a control mode.
4. The method of claim 1, further comprising, when the first module
has no data packet to transfer, receiving an indication that the
first module has no data packet to transfer.
5. The method of claim 1, further comprising assigning an address
to each of the first and second modules.
6. The method of claim 1, further comprising associating at least
one pipe with each of the first and second modules.
7. The method of claim 1, wherein the medical device comprises at
least one of a therapy control module, a user interface module, and
a patient parameters module.
8. The method of claim 1, wherein the medical device comprises a
defibrillator.
9. A method for programming a module of a medical device, the
method comprising: transferring program data to the module using a
USB protocol; and storing the program data in a memory associated
with the module.
10. The method of claim 9, further comprising encoding the program
data using an NRZI encoding scheme.
11. The method of claim 9, further comprising transferring the
program data in one of a bulk data transfer mode, an interrupt
mode, and an isochronous mode.
12. The method of claim 9, wherein the medical device comprises at
least one of a system controller, a therapy control module, a user
interface module, and a patient parameters module.
13. The method of claim 12, wherein at least one of the system
controller, the therapy control module, the user interface module,
and the patient parameters module comprises a serial data interface
to transfer data using the USB communication protocol.
14. The method of claim 12, wherein the medical device comprises a
defibrillator.
15. A processor-readable medium containing instructions for causing
a processor in a medical device to: transmit a USB token packet to
a first module of the medical device; when the first module has a
data packet to transfer, receive the data packet from the first
module; and transfer the data packet to a second module of the
medical device using a USB protocol.
16. The processor-readable medium of claim 15, further containing
processor-executable instructions for encoding the data packet
using an NRZI encoding scheme.
17. The processor-readable medium of claim 15, further containing
processor-executable instructions for transferring the data packet
in one of an isochronous mode, an interrupt mode, a bulk data
transfer mode, and a control mode.
18. The processor-readable medium of claim 15, further containing
processor-executable instructions for, when the first module has no
data packet to transfer, receiving an indication that the first
module has no data packet to transfer.
19. The processor-readable medium of claim 15, further containing
processor-executable instructions for assigning an address to each
of the first and second modules.
20. The processor-readable medium of claim 15, further containing
processor-executable instructions for associating at least one pipe
with each of the first and second modules.
21. The processor-readable medium of claim 15, wherein the medical
device comprises at least one of a therapy control module, a user
interface module, and a patient parameters module.
22. The processor-readable medium of claim 15, wherein the medical
device comprises a defibrillator.
23. A processor-readable medium containing instructions for causing
a processor in a medical device to: transfer program data to a
module of the medical device system using a USB protocol; and store
the program data in a memory associated with the module.
24. The processor-readable medium of claim 23, further containing
processor-executable instructions for encoding the program data
using an NRZI encoding scheme.
25. The processor-readable medium of claim 23, further containing
processor-executable instructions for transferring the program data
in a bulk data transfer mode.
26. The processor-readable medium of claim 23, wherein the medical
device comprises at least one of a system controller, a therapy
control module, a user interface module, and a patient parameters
module.
27. The processor-readable medium of claim 26, wherein at least one
of the system controller, the therapy control module, the user
interface module, and the patient parameters module comprises a
serial data interface to transfer data using the USB communication
protocol.
28. The processor-readable medium of claim 23, wherein the medical
device comprises a defibrillator.
29. A medical device comprising: a system control module; a
plurality of functional modules; and a system bus coupled to the
system control module and to the plurality of functional modules,
the system bus arranged to transfer data packets between the
functional modules and the system control module according to a USB
protocol.
30. The medical device of claim 29, wherein the plurality of
functional modules comprises a therapy control module.
31. The medical device of claim 30, wherein the therapy control
module comprises a defibrillator electrode.
32. The medical device of claim 29, wherein the plurality of
functional modules comprises a user interface module.
33. The medical device of claim 32, wherein the user interface
module is communicatively coupled to at least one of a keyboard, a
display screen, a strip chart recorder, an LED arrangement, a
rotary encoder device, and a touch screen.
34. The medical device of claim 29, wherein the plurality of
functional modules comprises a patient parameters module.
35. The medical device of claim 34, wherein the patient parameters
module is configured to obtain at least one of multi-lead ECG
measurements, EEG measurements, vital sign measurements,
non-invasive blood pressure (NIBP) measurements, invasive blood
pressure measurements, temperature measurements, ETCO.sub.2
information, and SpO.sub.2 information from a patient.
36. The medical device of claim 29, wherein the plurality of
functional modules comprises an expansion module to communicate
data with at least one device external to the medical device
system.
37. The medical device of claim 36, wherein the expansion module is
selected from the group consisting of: a USB-compatible root hub, a
hub, a simple device, and a complex device.
38. The medical device of claim 29, wherein the data packets are
encoded using an NRZI encoding scheme.
39. The medical device of claim 29, wherein the data packets are
transferred in at least one of an isochronous mode, an interrupt
mode, a bulk data transfer mode, and a control mode.
40. The medical device of claim 29, wherein the system control
module is configured to assign addresses to the functional
modules.
41. The medical device of claim 29, wherein the system control
module is configured to associate pipes with the functional
modules.
42. The medical device of claim 29, wherein the medical device
comprises a defibrillator.
Description
TECHNICAL FIELD
[0001] The invention relates generally to medical devices and, more
specifically, to communication between modular components of a
medical device.
BACKGROUND
[0002] Ventricular fibrillation and atrial fibrillation are common
and dangerous medical conditions that cause the electrical activity
of the human heart to become unsynchronized. Loss of
synchronization may impair the natural ability of the heart to
contract and pump blood throughout the body. Medical personnel
treat fibrillation by using a defibrillator system to apply a
relatively large electrical charge to the heart. If successful, the
charge overcomes the unsynchronized electrical activity and gives
the natural pacing function of the heart an opportunity to
recapture and reestablish a normal sinus rhythm.
[0003] Defibrillator systems are medical instruments that may have
multiple components, including, for example, a defibrillator to
apply an electrical shock to the heart of a patient, and an
electrocardiogram (ECG) monitor to evaluate the condition of the
patient. More particularly, the monitor records and analyzes an ECG
signal from the patient, while the defibrillator produces a
high-energy defibrillation pulse to terminate ventricular or atrial
fibrillation.
[0004] One or more of these components may incorporate several
modules. The defibrillator, for example, may include modules for
obtaining information from the patient, interacting with the
operator of the defibrillator, and delivering therapy to the
patient. This modular approach facilitates customization of the
defibrillator to the needs of the particular application. For
example, a user interface module may be selected based on the level
of experience of the expected operator of the defibrillator.
[0005] The defibrillator modules typically communicate with each
other using a serial data connection. In some conventional
defibrillators, inter-module communication occurs over an RS-232
connection. Other conventional defibrillators use various types of
serial data connections, including, for example, I.sup.2C,
Microwire, or SPI connections. These types of connections have a
number of disadvantages. For example, the bandwidth realized by
these connections may be too low for certain applications. In
addition, these connections lack extensibility. That is,
flexibility in allocating functionality among various modules is
limited.
SUMMARY
[0006] In general, the invention facilitates improved inter-module
communication within a medical device system, such as an automated
external defibrillator (AED), by using a serial data interface
based on the USB specification to transfer data between modules.
USB-type interfaces have conventionally been used to connect
devices externally, e.g., to connect various types of peripheral
devices to a personal computer. According to the principles of the
invention, however, a USB-type interface connects devices or
modules internally within a medical device system. This interface
transfers data using the USB data communication protocol and
complies with USB specifications with respect to signal integrity
and impedances, but employs a physical connector module designed
for the space-limited environment within a medical device
system.
[0007] The invention may offer several advantages. For instance,
data transmission rates may be improved significantly, thereby
providing ample communication bandwidth for a variety of medical
device applications. Further, the serial interconnect nature of the
USB interface reduces the number of physical interconnects that are
needed to support the interface, thereby reducing the design
constraints on the medical device system. Costs associated with
manufacturing the medical device system may also be reduced.
[0008] One embodiment is directed to a method for transferring data
between modules of a medical device using a USB protocol. A USB
token packet is transmitted to a first module of a medical device
system. When the first module has a USB data packet to transfer,
the data packet is received from the first module. The data packet
is transferred to a second module of the medical device system.
Modules of the medical device may be programmed or upgraded in this
manner.
[0009] Other implementations include defibrillators that carry out
these methods, as well as processor-readable media containing
instructions that cause a processor within a medical device to
perform these methods. For example, in one embodiment, a medical
device includes a system control module, functional modules, and a
system bus coupled to the system control module and to the
plurality of functional modules. The system bus transfers data
packets between the functional modules and the system control
module according to the USB protocol. The functional modules may
include, for example, a therapy control module that controls a
therapy device, such as a set of defibrillator electrodes, a user
interface module, and a patient parameters module.
[0010] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a block diagram illustrating a defibrillating
system configured according to an embodiment of the invention.
[0012] FIG. 2 is a plan view of a connector module for connecting a
device or module to the system controller of FIG. 1.
[0013] FIG. 3 is a flow diagram illustrating an example mode of
operation of the defibrillator system of FIG. 1.
DETAILED DESCRIPTION
[0014] FIG. 1 is a block diagram illustrating a defibrillating
system in which the invention may be practiced. When activated by
an operator 10, a defibrillator 12 administers one or more electric
shocks via defibrillator electrodes to a patient 16. Defibrillator
12 may be implemented, for example, as an automated external
defibrillator (AED).
[0015] Operation of defibrillator 12 is controlled by a system
controller 18 that is connected to a system bus 20. System
controller 18 may be implemented as a microprocessor that
communicates control and data signals with other components of
defibrillator 12 using the USB protocol via system bus 20. These
components may include functional modules, such as therapy control
module 14 or other therapy control modules, a patient parameters
module 22, and a user interface module 24.
[0016] Therapy control module 14 causes defibrillator electrodes
(not shown) to deliver electric shocks to patient 16 in response to
control signals received from system controller 18 via system bus
20. Therapy control module 14 may include, for example, charging
circuitry, a battery, and a discharge circuit. Any or all of these
components can be controlled by system controller 18.
[0017] Patient parameters module 22 may include electrocardiogram
(ECG) leads or other inputs. Patient parameters module 22 collects
information from patient 16, including, for example, vital signs,
non-invasive blood pressure (NIBP) measurements, and SpO.sub.2
information. Other information relating to patient 16 may be
collected by patient parameters module 22, including, but not
limited to, EEG measurements, invasive blood pressure measurements,
temperature measurements, and ETCO.sub.2 information.
[0018] User interface module 24 receives input from operator 10 and
outputs information to operator 10 using any of a variety of input
and output devices. For example, operator 10 may use keys to input
commands to defibrillator 12 and receive prompts or other
information via a display screen or LED indicators. As an
alternative, the display screen may be implemented as a
touch-screen display for both input and output. In addition, user
interface module 24 may print text reports or waveforms using a
strip chart recorder or similar device. User interface module 24
may also interface with a rotary encoder device.
[0019] User interface module 24 provides input received from
operator 10 to an operating system 26 that controls operation of
defibrillator 12 via system controller 18. Operating system 26 may
be implemented as a set of processor-readable instructions that are
executed by system controller 18. When defibrillator 12 is
activated, operating system 26 causes therapy control module 14 to
deliver therapeutic shocks to patient 16 via defibrillator
electrodes according to an energy protocol.
[0020] As described above, system controller 18, therapy control
module 14, patient parameters module 22, and user interface module
24 are connected to each other via system bus 20. According to an
embodiment of the invention, system bus 20 is compatible with the
USB standard. Implementing system bus 20 as a USB-compatible bus
offers several benefits. Advantageously, these modules may
communicate with each other using significantly fewer interconnects
compared to other communication schemes. For example, one
conventional interconnect technique uses a peripheral component
interconnect (PCI) bus that, in some implementations, uses more
than one hundred interconnects. As a result, systems using a PCI
bus must satisfy strict design constraints, such as size and power
constraints. By contrast, USB-compatible system bus 20 may use only
four interconnects, facilitating implementation within
significantly fewer design constraints. Moreover, the USB
communication protocol is simple, reducing the complexity of the
logic required in USB support chips. The reduced constraints and
simple communication protocol lead to lower costs of production, as
well as improved reliability.
[0021] For purposes of inter-module communication, system
controller 18, therapy control module 14, patient parameters module
22, and user interface module 24 may be considered USB devices.
System controller 18 acts as a host controller that initiates all
data transfers between the other modules. In addition to system
controller 18, therapy control module 14, patient parameters module
22, and user interface module 24, other modules or devices can also
be connected to system bus 20. For example, an expansion module 28
may allow system controller 18 to control a device 30 external to
defibrillator 12. External device 30 may be a USB root hub or a USB
hub connected to other devices, such as data acquisition devices or
other USB-compatible devices. Using a USB hub, many devices can be
connected to defibrillator 12 for a variety of purposes. Some such
devices include, but are not limited to, a printer, a bar code
scanner, a computer keyboard, or a data transfer device. These
devices may either be simple devices or complex devices as defined
in the USB specification.
[0022] FIG. 2 is a plan view of a connector module 50 for
connecting a device or module to system controller 18. Connector
module 50 includes a number of pins 52, 54, 56, and 58 that may be
inserted into appropriate receptacles in devices or modules to
transfer ground and data signals. For example, in one embodiment,
pins 52 and 54 may be used for ground, while pins 56 and 58 may be
used to transfer data signals. The allocation of ground and data
lines among pins 52, 54, 56, and 58 may be selected to satisfy
impedance requirements. Allocating two pins to ground connections
allows greater flexibility in impedance matching, potentially
improving signal integrity. As an alternative, a single pin may be
allocated to ground, such that connector module 50 may include only
three pins, rather than four as shown. In addition, one or more of
system controller 18, therapy control module 14, patient parameters
module 22, and user interface module 24 may incorporate impedance
matching circuitry to satisfy the impedance requirements of the USB
standard, thereby meeting USB signal integrity requirements.
[0023] Connector module 50 may be used to connect any of the
devices or modules internal to defibrillator 12, e.g., system
controller 18, a therapy control module 14, patient parameters
module 22, user interface module 24, and expansion module 28, to
system bus 20. Expansion module 28 has a USB port for connecting an
external USB-compatible device to system bus 20 via a conventional
flex circuit cable that meets USB specifications for impedance and
signal integrity. The flex cable allows expansion module 28 to
reside within defibrillator 12 at some distance, e.g.,
approximately 2-12 inches (5-30 cm) away from system controller 18.
In addition to carrying the USB-standard signals, the flex cable
may also carry several additional signals that do not relate to USB
communication. While not required, the flex cable may also be used
to connect other devices or modules internal to defibrillator 12,
such as user interface module 24. External devices 30 may be
connected to expansion module 28 via a conventional USB cable.
[0024] While the physical interface between the various devices or
modules and system bus 20 differs from the USB standard,
communication between the devices conforms to the USB communication
protocol, as well as USB specifications relating to impedance and
signal integrity. Accordingly, conventional software and hardware
development tools designed for the USB standard can be used with
little, if any, modification to develop additional devices for use
in conjunction with defibrillator 12. Development costs are thereby
reduced.
[0025] Software for transferring data between devices or modules of
defibrillator 12 may incorporate conventional USB software with
slight modifications. For example, the lower levels of the
communication stack may be modified to support the particular
processor and system controller 18 used in defibrillator 12. The
software may be implemented as a set of computer-executable
instructions stored in some form of computer readable media.
Computer readable media can be any available media that can be
accessed by defibrillator 12. By way of example, and not
limitation, computer readable media may comprise computer storage
media and communication media. Computer storage media includes
volatile and nonvolatile, removable and nonremovable media
implemented in any method or technology for storage of information,
such as computer readable instructions, data structures, program
modules, or other data. Computer storage media includes, but is not
limited to, random access memory (RAM), read only memory (ROM),
EEPROM, flash memory or other memory technology, CD-ROM, digital
versatile discs (DVD) or other optical storage, magnetic cassettes,
magnetic tape, magnetic disk storage or other magnetic storage
devices, or any other medium that can be used to store the desired
information and that can be accessed by defibrillator 12.
Communication media typically embodies computer readable
instructions, data structures, program modules, or other data in a
modulated data signal such as a carrier wave or other transport
mechanism and includes any information delivery media. The term
"modulated data signal" means a signal that has one or more of its
characteristics set or changed in such a manner as to encode
information in the signal. By way of example, and not limitation,
communication media includes wired media, such as a wired network
or other direct-wired connection, and wireless media, such as
acoustic, RF, infrared, and other wireless media. Combinations of
any of the above computer storage media and communication media are
also included within the scope of computer-readable media.
[0026] FIG. 3 is a flow diagram illustrating an example mode of
operation that may be implemented by the USB software. Before any
data is transferred, system controller 18 assigns USB addresses to
devices or modules as they are connected to system bus 20 during a
process known as enumeration (70). These addresses are subsequently
used to address individual devices. In addition, when a device is
connected to system bus, associations between system controller 18
and one or more endpoints of the device are established (72). These
associations are known as pipes. A given device may have multiple
pipes. For example, user interface module 24 may have an endpoint
that supports a pipe for transferring data to user interface module
24 and another endpoint that supports another pipe for transferring
data from user interface module 24. When multiple pipes are
established, the available bandwidth of system bus 20 is allocated
among the pipes (74). For some pipes, bandwidth is allocated when
the pipe is established.
[0027] All devices must support a specially designated control
pipe. All devices support a common access mechanism for accessing
information through the control pipe. For example, system
controller 18 can access device information via the control pipe.
This device information may be categorized as standard information
whose definition is common to all devices, as class information
specific to the type or class of the device, or as vendor-specific
information. In addition to device information, system controller
18 may access USB control and status information via the control
pipe.
[0028] Other pipes may be used to transfer functional data and
control information between system controller 18 and other devices
via system bus 20. Such pipes may be either unidirectional or
bidirectional. Generally, data movement through one pipe is
independent from data movement in other pipes.
[0029] System bus 20 is a polled bus. That is, system controller 18
periodically polls (76) the devices connected to system bus 20 to
determine whether a device has data to be transferred to system
controller 18 or to another device connected to system bus 20. If
there is no data to be transferred, system controller 18 repeats
polling the devices (76) until a device indicates that it has data
to transfer.
[0030] When a device indicates that it has data to transfer, system
controller 18 begins a transaction to transfer the data. Data
transfers may involve the transmission of up to three packets. Each
transaction begins when system controller 18 sends a USB packet,
known as a token packet (78), describing the type and direction of
transmission, an address designating a device or module, and an
endpoint number that designates a specific endpoint associated with
the device. The device or module designated by the address selects
itself by decoding the appropriate address fields. In a given
transaction, data is transferred either from system controller 18
to the selected device or from the selected device to system
controller 18. The token packet specifies the direction of data
transfer. The source of the transaction then either sends a data
packet (80) or indicates that the source has no data to transfer.
The destination may then respond with a handshake packet that
indicates whether the transfer was successful (82).
[0031] System bus 20 may transfer data in a number of different
modes. Control data, for example, is transferred in a control mode
to configure a device when it is initially connected to system bus
20. Another transfer mode, known as a bulk data transfer mode, is
used to transfer data that is generated or consumed in relatively
large and bursty quantities, e.g., data transferred to a strip
chart recorder. Bulk data is sequential. Reliable exchange of data
is ensured at the hardware level by using error detection and
correction techniques. The bandwidth taken up by bulk data may
depend on other data transfer activities occurring on system bus
20.
[0032] Some devices or modules that send relatively small amounts
of data may transfer data in an interrupt mode. In the interrupt
mode, data may be presented for transfer to or from a device at any
time and is delivered by system bus 20 at a rate no slower than is
specified by the device. Interrupt data typically consists of event
notifications or characters that are organized as one or more
bytes. One example of interrupt data is characters input via the
keys connected to user interface module 24.
[0033] Other devices or modules may transfer data in an isochronous
mode. Isochronous data is continuous and real-time in creation,
delivery, and consumption. To the extent that patient parameters
module 22 collects real-time vital sign measurements from patient
16, for example, patient parameters module 22 may transfer data in
the isochronous mode. In this mode, data streams between the device
and system controller 18 in real-time without error correction.
Timing-related information does not need to be explicitly
transferred, as this information is implied by the steady rate at
which the isochronous data is received and transferred. To maintain
correct timing, isochronous data must be delivered at the same rate
at which it is received. Accordingly, isochronous data is sensitive
to the delivery rate. In addition, isochronous data may also be
sensitive to delivery delays. For isochronous pipes, the bandwidth
required may be based on the sampling characteristics of the
associated function. The latency required may be related to the
buffering available at each endpoint of the pipe.
[0034] Regardless of the data transfer mode, data transferred via
system bus 20 may be encoded using a conventional inverted non
return to zero (NRZI) encoding scheme. In this scheme, a value of
"0" is indicated by a transition in the data signal, while a value
of "1" is indicated by the absence of a transition in the data
signal. Thus, for example, a string of 1's would result in a long
period without signal transitions. In order to force transitions in
the data signal, a bit stuffing technique is used to insert a zero
after a sequence of consecutive 1's of a prescribed length, e.g.,
after a sequence of six consecutive 1's. Accordingly, if a device
receives a sequence of consecutive 1's that exceeds the prescribed
length, the device may conclude that an error has occurred and
ignore the data packet.
[0035] By way of example, the data transfer technique of FIG. 3 may
be used to reprogram a processor embedded in system controller 18,
therapy control module 14, patient parameters module 22, or user
interface module 24. Program data, such as a software upgrade, may
be transferred via system bus 20 to the device to be reprogrammed.
The software upgrade may then be stored using, for example, a RAM
device or a flash memory.
[0036] The data transfer technique of FIG. 3 can also be used to
control the functions of the various modules of defibrillator 12.
For example, system bus 20 can be used to effect the delivery of
therapeutic shocks to patient 16 via defibrillator electrodes. In
this mode of operation, operator 10 uses the external keys to
activate defibrillator 12. Operator 10 may use the external keys,
for example, to select an energy protocol to be applied to patient
16. User interface module 24 transfers the key input to system
controller 18 via system bus 20.
[0037] System controller 18 then generates the appropriate control
signals for controlling the defibrillator electrodes to deliver the
electric shock or shocks to patient 16 as specified by the selected
energy protocol. System controller 18 transfers the control signals
to therapy control module 14. These control signals may include
control signals for controlling the charging circuitry, the
discharge circuitry, or both. Therapy control module 14 operates
the charging and discharge circuitry as directed by the control
signals, thereby causing the defibrillator electrodes to deliver
the correct electric shock or shocks to patient 16.
[0038] Various embodiments of the invention have been described.
The invention may be used in AEDs as well as other types of
defibrillators. In addition, while several embodiments of the
invention have been described in the context of a defibrillator,
the principles of the invention may be practiced in other types of
medical devices, including, but not limited to,
defibrillator/pacemakers and therapy devices for other medical
conditions, such as stroke and respiratory conditions. These and
other embodiments are within the scope of the following claims.
* * * * *